IL32987A - Fluid bearing device with self-regulating action - Google Patents

Description

FLU BEARING WITH FLUID BEARING DEVICE WITH ACTION Abstract of the Disclosure A fluid cushion device is made from flat nonporous sheets providing a minimum thickness when The when form a torus attached with a fluid tight seal to the lower surface of the platform to define a plenum chamber within the seal and the lowermost extremity of the A fluid supply orifice conducts fluid under pressure through the bottom surface of the platform into the plenum and one of the sheets has defined within it a fluid inlet aperture held in general registry the fluid supply orifice when the cushion is Once inflated additional apertures in the torus provide surge pressure regulating outlets from the cushion exiting into the Large area pads are positioned around the periphery of the torus and within the boundary formed by the inner edges of the sheets to provide a distributed bearing support when the torus is deflated without wrinkling or pinching the For higher pressures and heavier a retainer ring is fastened between the bonded sheet and the platform to provide a structural supplement to the fluid tight The sheets may be overlapped between the retainer ring and the with the joint between the overlapped sheets exposed to the plenum so that any escaping fluid the joint from within the torus escapes into the plenum and any escaping fluid from the plenum is received into the To resist nonuniform expansion of the sheets under high the sheets may be formed of laminated plies of nonporous rial having the warp of adjacent plies biased from one This invention relates to fluid cushion devices and more particularly to low profile devices rating means for providing flow load distribution and heavy The use of fluid cushion devices for supporting large loads has a principal advantage of distributing the relatively low pressure of the fluid over a large area of the floor or ground surface over which the device travels while supporting a heavy load on a This is a particular advantage when the floor such as in an by its construction will not tolerate high concentrated loads such as might be duced by normal wheel casters and similar In the patent to an air cushion is used to support a heavy home appliance such as the erator The air bearing is used for supporting the appliance during the time that it is moved in and out of its normal position for cleaning or for other It is that adjustable leveling screws 14 are tioned in each bottom corner of the appliance to provide its normal support when the air cushion is Since these supports have such a small area they often duce dimples in the floor surface and can actually puncture the floor if the surface cannot tolerate such high concentrated loads In the patent to a rather plicated valving system is disclosed for regulating the flow of air between the flexible tubular member and the plenum portion of the air caster to accommodate load concentrations on the platform supported by the air cushion In the previously mentioned patent to small bleed positioned around the periphery of the inflatable are from the inflated chamber outside of the plenum area once the inflated chamber becomes distorted due to an increased There has been found that the lower pressures and high volumes of air used for air cushions are readily available in many industrial for supporting heavier loads requiring higher pressures and higher volumes of such cushion devices have been generally considered not feasible because the compressor capacity of the plant could not serve such high volume requirements even at a relatively lov When fluid cushion devices are not in their volume is generally reduced due to the deflation of the torus or but ordinarily the structure of the material forming the torus is and upon deflation does not sent a flattened In the deflation of the torus material often produces wrinkles which in time will produce points of weakness and failure within the As fluid cushion devices have been tried for carrying higher loads it has been noted that the torus material tends to stretch out of shape yielding wrinkles and other surface continuities in the torus producing an uneven ride for the load being carried and fluid bearing In view of the inherent limitations and problems lated above with regard to the design and utilization of less load carrying it is the principal object of the instant invention to provide a generally improved fluid device suitable for supporting and transporting higher loads than previously carried by air cushion It is another object of the instant invention to vide a generally improved torus configuration for fluid cushion devices which permits the load carrying torus when deflated to According to invention there is provided a fluid bearing an annular body which is hollow and has flexibl upper and lover walls so as to be inflatable to form a and a rigid backing member which is disposed one of the aforesaid flexible annula shaped walls of the body and interconnected with the body around the entire circumSerenee thereof so as to orm a plenum within the opening defined by the torus when the body is the aforesaid interconnection between the body and the vacking member being radially outwardly spaced from the inner peripheral edge of the between the aforesaid one wall of the body and the backing so that on inflation of the the inner peripheral edge portion of the one wall is free to separate om the vacking member to form a space therebetween which is in open communication with the plenum at the adjacent inner and outer peripheries respectively and inflating means for introducing pressurized initially directly into said annular body to cause same to separate from the vacking member to form the spandrel like and then directly into said space and said plenum and indirectly therethrough into said annular According to another aspect of the invention there is provided a bearing cushioning device comprising means defining a moans defining a fexible walled torus depending from a ight seal with one surface of said a plenum defined by said torus between said seal and the lowermost extrmity of said means supplying fluid under pressure directly into plenums and opening means defined by a portion of said torus bordering said plenum general registry with said luid supply means for communicating said under pressure between said plenum and the interior of said torus or in torus m dfiin u l inlet fo in registry for directly receiving fluid into said torus in said deflated and for sharing said fluid with said in said inflated To provide significant increased strength to the permitting the use of higher pressures and fluid mediums such as the torus sheets are formed b plies of nonporous material haying the weave of p ies of from one another for increasing dimensional stability and making more uniform any distortion in the For large torus devices a retainer ring is used to squeeze the torus at the fluid tight seal zone against the The overlapping of nonporous sheets the torus tween the retainer ring and the platform is arranged so that any fluid leaking the overlapped sheets will be trapped within the torus or within the plenum chamber rather than caping to the These and other features and advantages of the vention will become more clearly apparent from the following detailed description which is to be read with ence to the accompanying In the Figure 1 is a bottom plan view of a form including pressure fluid load carrying cushions of the present Figure 2 is a side section view taken along the line of Figure Figure 3 is a top plan view of a single fluid cushion with the platform removed for Figure 4 is a side sectional view taken line of Figure Figure 5 is an exploded perspective view of one form of the instant and Figure 6 is a side section view similar to Figure 4 but of a different embodiment of the fluid cushion device in accordance with the present shown in the bottom plan view of Figure the load carrying device 1 is illustrated as including a backing plate 4 such as a load carrying platform having a bottom surface 5 upon which are mounted fluid bearing casters 9 and These casters are referred to herein as fluid bearing cushions and may be designed to form a variety of plan forms with results obtained by use of a doughnut or torus plan The horizontally from bottom surface 5 of backing plate 4 to define with its inner edges 23 a central opening Positioned within central opening 24 and attached to bottom surface 5 is central landing 12 depending horizontally from the surface 5 a thickness greater than the collapsed thickness of deflated torus Positioned around the outer edges 26 of torus 17 are corner landing pads 14 of a similar material and thickness to that of central landing pad 12 and also bonded to and depending from bottom surface 5 of backing plate As shown in Figures 2 through 5 cushion or torus 17 is composed of an upper skirt sheet 19 held with a suitable hesive in a bonded fluid tight sealed forming a sealing zone with lower surface 5 of platform Lower skirt sheet 21 is bonded to upper skirt sheet 19 at their outer edges 26 which are stitched and reinforced by outer perimeter binding 28 in the form of a A fluid type seal is ensured at this juncture by the use of an outer meter seal ring 30 which may be formed of a vulcanized within the torus chamber 31 opposite outer perimeter binding The inner edges 23 of upper and lower skirt sheets 19 and 21 are likewise stitched and bound together in a fluid tight seal which is reinforced by inner perimeter binding tape Thus formed the upper and lower skirt sheets 19 and 21 fine an inflatable torus 17 having a noninflated flat profile such as shown in dashed lines in Figure 4 completely protected by the central and corner landing pads 12 and 14 so as not to pinch the fabric forming the skirt sheets 19 and A plenum chamber 33 is defined the inner periphery of torus 17 bottom surface 5 within seal zone the surface of the central landing pad and the lowermost extremity 46 of lower sheet 21 adjacent the floor surface A supply of therefore not to the fluid supply inlet 40 defined in backing plate 4 as it forms a fluid communication through plate 4 into plenum chamber As shown in dashed lines in Figure the torus inlet aperture defined in the upper skirt sheet is positioned in general registry vrith fluid supply inlet 40 torus 17 is in its collapsed Also defined within the portion of upper 19 extending from the seal zone 20 to inner edge 23 are a series of surge outlet apertures 44 which permit communication of the fluid under pressure between torus chamber 31 and plenum chamber With such an inlet and aperture arrangement it is possible to inflate torus chamber 31 partially before a load is supported by cushion 10 by the panding configuration of torus 17 away from surface At the outset fluid under pressure is communicated from fluid supply inlet 40 directly through torus inlet aperture 42 into chamber As the configuration of torus 17 becomes more the portion of upper skirt sheet 19 between seal 2one 20 and the inner edge 23 pulls away from bottom surface 5 of backing plate forming a space therebetween and permitting the fluid under pressure from supply inlet 40 to be shared tvreen plenum chamber 38 and torus chamber As the pressure builds up in plenum chamber 38 and torus chamber 31 the bearing seal betvreen the lowest extremity 46 of skirt sheet 21 and floor surface 16 is broken and a perimetrical throttling gap 48 is developed which permits fluid bearing flow alloiiing frictionless motion between platform 4 and ground surface 16 as long as the throttling gap 48 is maintained through a continuous supply of the fluid under pressure from fluid supply inlet As balanced loads or uneven floor surfaces are an crease of the fluid supply from plenum chamber 38 out through the throttling gap 48 is With previously used valving increase in the pressure within torus chamber 31 causing ditional stiffness and perhaps grounding out of caster by elimination of the throttling gap before the increased fluid under pressure could be supplied to plenum chamber 38 and the throttling gap ith the instant tural skirt surge outlets have an aggregate volume exceeding the volume of skirt inlet aperture 42 and thereby permit a quick means of pressure equalization and communication for the fluid under pressure between torus chamber 31 and plenum chamber to provide a To enhance the strength of the seal between torus 17 and the backing plate a clamping ring 50 may be positioned within torus chamber 31 and tightly fastened by suitable fastening means 52 to the backing plate 4 to squeeze upper skirt sheet 19 firmly and securely against bottom surface 5 in sealing zone With this construction caster 10 has the ability to withstand sudden abutments and ridges on the floor without breaking the fluid tight seal with surface In a typical use application for fluid cushion Casters similar in construction to those shown in Figures 1 to it has been found that a combination of nonporous 32 ounce nylon fabric is suitable for torus skirts 19 and A one inch wide nylon tape webbing having pounds tensile strength is used for the outer perimeter binding tape 28 and a two inch wide twill nylon tape having pounds tensile is used for the inner perimeter ing tape For a caster having a twelve inch outside a one inch sealing zone 20 is adequate with torus inlet aperture 42 having a diameter of inch with thirty two inch diameter surge outlets 44 positioned around the inner be of rubber material having a 60 durometer and psi tensile strength with a surface area of approximately of the equivalent area of the fluid caster With this ratio of surface area between the pads and it is possible to distribute the load from the backing plate 4 through the pads without concentrating the load when the torus 17 is Greater area for corner landing pads 14 may be provided if there is sufficient area available on ing surface 5 of backing plate By positioning central ing pad 12 within the plenum chamber 38 the span between ports for backing plate 4 is reduced when the torus 17 is thereby eliminating the surface distortion and load concentrations which are caused by large unsupported spans of backing plate As shown in Figure a second embodiment 61 of a suitable fluid caster is illustrated in a view similar to that shown in Figure 4 for the first embodiment For this reason similar numbers are used for similar structural In this embodiment the caster 61 has been reinforced generally to increase its load carrying capacity and to reduce the fluid losses and resulting bearing inefficiencies caused by wrinkles and nonuniform expansion of torus The fabric for the lower skirt member the inner skirt member 66 and upper skirt member 67 is increased in its strength by using a laminated nonporous material having the warp of adjacent plies positioned at an angle from one such as to crease the dimensional stability of caster 61 as it becomes inflated with greater pressures for carrying greater loads than the single ply caster 10 previously It has been found in comparison tests that a inch outside diameter caster having a construction similar to that shown per minute in maintaining the air bearing with 18 pounds per square inch pressure at the throttling gap This is to be compared with a double ply of a inch diameter bearing made in accordance with the construction shovm in Figure utilizing the oblique relationship between the warp of jacent plies of the skirt to produce the same load carrying capability with only 3 cubic feet of air per minute It is the uniformity of expansion and therefore the lack of wrinkles in the skirt material adjacent to the ground level which apparently produces the increased efficiency of second embodiment caster 61 as compared to first embodiment caster It has also been found that by utilization of the second ment caster construction it is possible to significantly crease the load carrying capacity of a cushion air bearing caster through the increase of pressure of the An operating pressure of 55 pounds per square utilizing water as the fluid under provides a significant increase in load carrying capacity for fluid bearing pallets and permits the utilization of normal water supply pressure available at most plant This eliminates the need for high volume air pressors and is particularly well suited for use in carrying large structural parts from one position to another in a In more detail it is noted from Figure 6 that inner skirt sheet 66 is overlapped at joint 72 with upper skirt sheet 67 in the sealing zone 70 and these overlapped sheets are clamped between clamping ring 50 and bottom surface This sequence of overlap between sheets 66 and 67 increases the fluid integrity of caster 61 since any fluid escaping from plenum chamber 38 through joint enters into torus chamber 31 and any fluid under pressure passing from torus chamber 31 through seen that the sequence of overlap with upper skirt sheet which is exposed to the exterior of caster 61 positioned mediately adjacent bottom surface 5 of backing plate and inner sheet positioned adjacent the lower surface of the upper sheet 67 and in immediate contact with clamping ring produces a stronger more leak proof Although some tests have shown that the relative tions between supply inlet 40 and torus inlet 42 need not always be in overall results indicate that these inlets should be in general registry for On some tests the supply inlet was positioned in the center of central pad 12 and proper inflation of the torus and formation of the fluid bearing occurred between the lowermost extremity of the torus and the In other with a similar supply to torus inlet the temporary seal between the torus and ground surface failed to be maintained long enough to properly inflate the torus such that a proper fluid bearing could not be Because of the variety of variables including torus stiffness of the torus distance between the platform to torus seal and the relative radial positions of the orifice design of the supply but to name a it is difficult to state what range of nonalignment between the supply and torus inlets could be used without producing unreliable It is believed clear however that those skilled in the art could easily mine with rather straightforward tests the range of nonalignment for producing satisfactory results with any particular set of For this reason the claims refer to to include direct alignment and other special ships between the supply and torus inlet openings which produce reliable torus inflations and fluid bearing insufficientOCRQuality

Claims (1)

1. 32987/2 WHAT IS CLAIMED IS: 1. A fluid bearing device comprising, in combination, an annula body which is hollow and has flexible uppe and lowe annula ly-shaped walls so as to be inflatable to form a torus, and a rigid backing member which is disposed opposite one of th aforesaid flexible annularly-shaped walls of the body and interconnected with the body around the entire circumference thereof so as to orm a plenum within the opening de ined by the torus when the body is inflated, the aforesaid interconnection between the body and the backing member being radially outwardly spaced from the inner perpheral edge of the body, between the aforesaid one wall of the body and the backing member, so that on inflation of the body, the inner peripheral edge portion of the one wall is free to separate from the backing member to form a spandrel-like space therebetween which is in openucommunicatlon with the plenum at the adjacent inner and outer peripheries thereof respectively, and in lating means for introducing pressurised fluid initially directly into said annular body to cause same to svparate from the backing member to form the spandrel-like space, and then directly into said spandrel- ike snyce and said plenum and indirectly therethrough into said annular body* 2· A device according to Claim 1, wherein said inflating means comprises an opening in the backing member spaced radially inwardly from the aforesaid interconnection* and an opening in the aforesaid inner peripheral one wall edge portion of the body* which are cooperatively disposed to that when the body As in a def ated condition and a stream of pressurized fuid is fed through the opening in the backing membe * initially the major portion of the stream is discharged into the bdd through the opening therein, 32987/2 to Inflate the body and to form the aforesaid spandrel-like space between the body and the backing member* and thereafter is discharged into the spandrel-like Space Itself for pressurisatlon of the plenum so that the torus can operate as a fluid bearing* 3* The device according to either of Claims 1 or 2, wherein the spandrel-like space is openly exposed to the plenum about the entire inner periphery thereof) so as to form a part of the plenum. 4. The device according to Claim 2 , wherein the opening in the packing member ie disposed opposite the spandrel- ike space in plan view, and the opening in the inner peripheral one vail edge portion of the body is in vertical registry therewith* 5· Th* device according to Claim 2* wherein the inner peripheral one wall edge portion of the body has a plurality of openings therein* 6» The device according to Claim 5 , wherein th openings in the inner peripheral one wall edge portion of the body are angularly spaced about the circumference o the body* 7. The device according to Claim 5» wherein the opening in the backing member is disposed opposite the spandrel-like space in plan view* and one of the openings in the inner peripheral one wall edge portion of the body is radially outwardly spaced from the remaining openings therein* and in vertical registry with the opening in the backing member. 8. The device according to any of Claims 1-7* wherein the other of the aoresaid lexible annularl -shaped walls of the body Is imperforate. 32987/2 beyond tu& opening defined by the body when the body is in a deflated condition* but which lies wholly within the opening defined by the torus when the body is in an in lated condition* 10. The device according to Claim 9, wherein the opening in the backing member is disposed adjacent the outer peripheral edhe of the pad. 11· The device according to Claim 1, wherein said inflating means comprises an opening in the aforesaid inner peripheral one wall edge portion of the body, and means operative at a point spaced radially inwardly from the aforesaid interconnection to discharge a stream of pressurised fluid into the body through said opening , to inflate the body and thereby form the aforesaid spandeel-like space between the body and the backing member , and operative thereafter on inflation of the body , at o discharge a stream of pressurized luid into the spandrel-like space itself for pressurization of the plenum so that the torus can operate as a luid bearing* 12. The device according to Claim 1, wherein said inf lating means comprises flui sppply inlet in the aforesaid Inner peripheral one wall edge portion of the body and means operatively disposed radially inwardly from the aforesaid interconnection in the acking member , to discharge a stream of pressurized fluid into the aforesaid spandrel-like space between the body and the backing member upon in lation of the body. 13. The device according to any of Claims 1-12 , wherein the bdoy has an annular retainer ring therein and the interconnection between the body and the backing member is formed by clamping the aforesaid one wall of the body between the retainer ring and the backing member to form a fluid tight connection. 14. The device according to Claim 13 , wherein the one wall 32987/2 edges which are c lamped between the retainer ring and the bakking member to form the outer and inner peripheral portions of the vail* 15. The device accordint to Claim 14, wherein Che overlapping edge of the outer peripheral sheet is disposed adjacent the backing member* 16· A fluid bearing cushion load-supporting device comprising means definin a platform means defining a flexible walled torus depending from a fluid tight seal with one surface of said platform; a plenum defined by said torus between said sea and the lowermost extremity of said torus | means supplying fluid under pressure directly into said plenum} and opening means de ined by a portion of said torus bordering said plenum in general registry with said fluid supply means for communicating said fluid under pressure between said plenum and the interior of said torus for Inflating said torus elevating said platform; said platform defining a supply inlet for sai f uid supply means opening into said plenum} and said torus opening and said supply inlet being positioned in registry for directly receiving said fluid into said torus in said de lated position and for sharing said luid with said plenum in said inflated position* 17· A fluid bearing cushion load-supporting device substantially as described with reference to and as Illustrated in the accompanying drawings* COHE ZEDEK & S PISBA H ! i v n t